 What
is keratoconus?
Keratoconus is an uncommon condition in which the normally
round, dome-like cornea (the clear front
window of the eye) becomes thin and develops a cone-like-bulge. Keratoconus literally
means a cone-shaped cornea. This abnormal shape can cause serious
distortion of vision.
What causes keratoconus?
Research indicates that keratoconus may be caused by an
excess of enzymes that break down the proteins within the corneal surface,
causing the cornea to thin and protrude.
The genetic inheritance of keratoconus has not clearly
been determined. Some researchers believe that genetics play a role,
since an estimated 10% of people with keratoconus also have a family
member with the condition. It appears that it may involve a number of
different genes. Blood relatives of someone affected with
keratoconus have minor changes in their corneas that may indicate that
keratoconus probably varies both in the specific genetic cause, as well as
in its expression within a family.
Vigorous eye rubbing can contribute to the disease
process. People with keratoconus should avoid rubbing their
eyes. This is sometimes very difficult because some allergies, which
cause itchy, irritated eyes, are more commonly associated in patients with
keratoconus.
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What are the symptoms of keratoconus?
Keratoconus usually affects
both eyes, though symptoms in each eye may differ. Symptoms
usually start to occur in people who are in their late teens and early
twenties and may include:
- mild blurring of vision
- slight distortion of vision
- increased sensitively to light
- glare
- mild irritation
Blurring and distortion of vision are the earliest symptoms of keratoconus. The disease will often progress slowly for 10 to 20 years,
then stop. In the early stages, vision may be only slightly
affected, causing glare, light sensitivity, and irritation. Each eye
may be affected differently. As the disease progresses and the
cornea steepens and scars, vision may become distorted. The rate of
progression varies. It will often progress slowly for 10 to 20
years and then suddenly stop. As the condition progresses,
most common symptoms include:
- increased blurring and
distortion of your vision
- increased nearsightedness or
astigmatism
- frequent eyeglass prescription
changes
Occasionally,
keratoconus can advance rapidly, causing the cornea to become
scarred. Scar tissue on the cornea causes the cornea to
lose its smoothness and clarity. As a result, even more
distortion and blurring of vision can occur.
A
sudden decrease in vision can occur if the cornea swells. The cornea
swells when the elastic part of the cornea develops a tiny crack, created
by the strain of the cornea's protruded cone-like shape. The selling
may persist for weeks or months as the crack heals and is gradually
replaced by scar tissue.
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How is keratoconus treated?
Treatment will often
depend on the severity of the condition. During early
stages, vision can be corrected with eyeglasses. If
eyeglasses cannot fully correct vision, rigid contact
lenses can make a remarkable difference in the clarity of vision.
Newer materials and designs enable many people with keratoconus to enjoy
wearing contact lenses longer. As the condition progresses, rigid
contacts may need to be worn so that light entering the eye is
refracted evenly and vision is not distorted. You should
also refrain from rubbing your eyes, as this can aggravate the
thin corneal tissue and make symptoms worse.
Other ocular conditions are
often seen in association with keratoconus, such as eyelid inflammation
(blepharitis) or atopic or allergic red eye (conjunctivitis). These
conditions can be treated with the appropriate drops and cleansing routine
to enable comfortable contact lens wear. Dr. Cano can advise you on
how to appropriately treat these conditions.
When good vision is no longer
possible with contact
lenses, a corneal
transplant may be necessary. This surgery is only necessary in
about 10-20% of patients with keratoconus. In a corneal
transplant, Dr. Cano removes the diseased cornea from your eye and
replaces it with a healthy donor cornea. While a corneal
transplant will relieve the symptoms of keratoconus, it may not provide
you with flawless vision; eyeglasses or contacts may still be needed to
achieve your best vision. Keratoconus is one of the most common
reasons for corneal transplant, and one of the most successful.
Dr. Cano will discuss the risks, benefits, and alternatives to surgery
as they pertain to your particular case.
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Why are regular medical eye examinations
important for everyone?
Eye disease can occur at any age. Many eye diseases
do not cause symptoms until the disease has done damage. Since most
blindness is preventable if diagnosed and treated early, regular medical
examinations by an ophthalmologist are very important. If you
are experience any optical difficulties, or just need a routine eye exam,
please make an appointment to see Dr. Cano or Dr. Manning.
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